/*   The MIT License
 *   
 *   Carina Engine
 *   Copyright (c) 2009 2010 2011 2012 Zdravko Velinov
 *   
 *   Permission is hereby granted, free of charge, to any person obtaining a copy
 *   of this software and associated documentation files (the "Software"), to deal
 *   in the Software without restriction, including without limitation the rights
 *   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *   copies of the Software, and to permit persons to whom the Software is
 *   furnished to do so, subject to the following conditions:
 *
 *   The above copyright notice and this permission notice shall be included in
 *   all copies or substantial portions of the Software.
 *
 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 *   THE SOFTWARE.
 */

#include "carina/filters.hh"
#include "carina/common/containers.hh"

#include <algorithm>

namespace Carina
{
void sobel_filter(const float* in, Vector4* out, unsigned w, unsigned h)
{
    float Gx, Gy;
    const float* ptr;
    for(unsigned i = 1; i < h-1; ++i)
        for(unsigned j = 1; j < w-1; ++j)
        {
            ptr = in + i*w + j;
            Gx = ptr[-1-(int)w] + 2*ptr[-1]      + ptr[-1+w]     - ptr[1-(int)w] - 2*ptr[1] - ptr[1+w];
            Gy = ptr[-1-(int)w] + 2*ptr[-(int)w] + ptr[1-(int)w] - ptr[-1+w]     - 2*ptr[w] - ptr[1+w];
            out[i*w + j].set(Gx, Gy, sqrtf(1.0f - Gx*Gx - Gy*Gy));
            out[i*w + j].xyz().normalize();
        }
}
}
